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Rational evaluation of surface irrigation systems should consider the effects of spatial variations in soil intake properties on advance trajectories and on the uniformity of infiltrated depths. The objective was to quantify the effects of spatial variations in infiltration parameters on the variability of advance trajectories and on infiltration depths. The soil properties were expressed as random space functions, and small perturbation analysis was applied to analytical solutions for the advance phase. This resulted in closed-form expressions relating the variability in soil properties to the variability in advance trajectories. The expressions were tested using Monte Carlo (MC) simulations. The results show good agreement between the analytical expressions and the simulated mean and variance of advance trajectories for a wide range of intake variabilities. In all cases, a sharp increase in the variance of advance times was observed toward the end of the field. This resulted in discrepancies between the simulated and the closed-form approximation for infiltration depths at large distances from the field inlet. The study provides a predictive tool for the evaluation of management strategies for surface irrigation in heterogeneous fields once the extent of spatial variability in soil intake properties has been estimated. Some applications for the estimation of uniformity and application efficiency are illustrated.

Maple syrup urine disease (MSUD) or branched-chain ketoaciduria is caused by a deficiency of the branched-chain [Alpha]-keto acid dehydrogenase (BCKAD) complex. This results in the accumulation of the branched-chain amino acids (BCAA) and branched-chain [Alpha]-keto acids (BCKA), which often produce severe neurological damage and mental retardation. The present studies focus on mutations in the E1[Alpha] gene of the BCKAD complex and their effects on the assembly of the E1 decarboxylase component of the enzyme complex. We have developed an efficient histidine-tagged bacterial expression system that allows the folding and assembly of E1[Alpha] and E1[Beta] subunits into the E1 heterotetramer ([[Alpha].sub.2][[Beta].sub.2]) in the presence of overexpressed chaperonins GroEL and GroES. The results of pulse-chase experiments with this bacterial expression system showed that a majority of the 15 known E1[Alpha] mutations, including the prevalent Y393N of Mennonite MSUD patients, decrease the rate of association of normal E1[Beta] with mutant E1[Alpha]. This results in limited or no assembly of mutant E1. it is concluded that the carboxy-terminal region of the E1[Alpha] subunit encoded by exons 7-9 is important for subunit interaction. To stably correct MSUD, we have developed a retroviral vector that contains a normal E1[Alpha] precursor complementary DNA. Transduction of cultured lymphoblasts from a Mennonite MSUD patient with this recombinant retroviral vector completely restored the rate of decarboxylation of BCKA. The normal decarboxylation activity in transduced MSUD cells remained stable without antibiotic selection during the 14-week study. The results provide a paradigm for the development of somatic gene therapy for MSUD. INDEXING KEY WORDS: maple syrup urine disease; branched-chain [Alpha]-keto acid dehydrogenase; protein assembly defect; retroviral gene transfer

The cumulative water demand (CWD) curve was used for validating and calibrating the unit command area (UCA) model, which predicts the aggregate water demands of individual command areas for the entire crop season. During the model calibration process, as presented in the companion paper, three important variables in the operation stage on the prediction of demand were found to be dominant in determining the CWD curve profile. The logistic function with three parameters, which is a particular form of the exponential-type function, was adopted for fitting the CWD curve. High correlations, were observed between the individual curve parameters and the field variables. Three parameters are management-allowable depletion (MAD), irrigation application uniformity (IAU), and initial soil moisture (ISM). Effectiveness of the equation developed for a particular UCA using the regression analysis was successfully demonstrated, and applicability for some other UCAs in the same water system was also recognized.

Simulation of aggregate water demands by areas commanded by canal and lateral turnouts is an important input to the operation and management of the irrigation delivery system. A computer simulation model to predict these command area water-demand functions was developed and reported by Keller in 1987. To test the validity of the model, data from an existing irrigation project in the Delta, Utah, area were used to simulate the aggregate irrigation demand of five turnouts operated on a demand basis. During the model calibration process, the influence of three important variables in the operation stage on the prediction of demand was identified using the cumulative water-demand curve. The key variables were: (1) Management-allowable depletion (MAD); (2) irrigation application uniformity (IAU); and (3) initial soil moisture (ISM).

The in vitro refolding of bovine E2c is mediated by chaperonin and the reconstitution of the 24-meric structure of E2 involves active trimeric intermediates. The three-dimensional structure of 24-mer inner core domain of the pyruvate dehydrogenase complex shows that the trimers are the basic functional units of E2.

Single-site mutations were constructed at positions Leu42 and Leu78 in the hydrophobic core of Escherichia coli thioredoxin to determine the effect on the thermostability and activity of the monomeric protein. All mutants remained active in the in vivo assembly of filamentous bacteriophages which indicated that the mutations elicited no effect on the functions of thioredoxin. However, the free energies of unfolding of the mutant proteins were destabilized due to the hydrophobic effect.

Introduction: It is important to prevent school dropout and to help students who have dropped out re-enroll in school. Dropping out of school is associated with an increased risk of unemployment, low salaries, and receiving social security or disability benefits. In this study, we interviewed participants in 'Guttas Campus' (The Boys' Camp), which is a group-based intervention that aims to support disengaged boys from the 9th grade and through their transition to high school. The intervention consists of a two-week learning camp. The students subsequently participate in mentoring groups, with teachers and other camp participants, for a period of 18 months. Objectives: We present a study of a school dropout prevention program. Methods: 16 students were interviewed qualitatively. The interview data were analysed by drawing on the method of Grounded Theory. Results: When the students who have completed the learning camp were asked what they believed were the most important and useful parts of the intervention, some common themes emerged: 1) The learning camp community provided a safe environment and helped give the participants learning and coping experiences that increased their self-confidence. 2) The students brought up the method of teaching, which they described as more persistent, adaptive and encouraging than they had been used to from regular school. 3) The students also mentioned the intervention's focus on character strengths such as willpower, self-control and optimism as central to increasing their motivation to learn. Conclusions: The students that were interviewed were generally positive to the intervention, as mentioned several factors that they believed were useful in increasing their motivation and ability to learn. Disclosure of Interest: None Declared [ABSTRACT FROM AUTHOR]

The carbohydrate response element binding protein (ChREBP) is a glucose-responsive transcription factor that plays a critical role in glucose-mediated induction of genes involved in hepatic glycolysis and lipogenesis. In response to fluctuating blood glucose levels ChREBP activity is regulated mainly by nucleocytoplasmic shuttling of ChREBP. Under high glucose ChREBP binds to importin α and importin β and translocates into the nucleus to initiate transcription. We have previously shown that the nuclear localization signal site (NLS) for ChREBP is bipartite with the NLS extending from Arg158 to Lys190. Here, we report the 2.5 Å crystal structure of the ChREBP-NLS peptide bound to importin α. The structure revealed that the NLS binding is monopartite, with the amino acid residues K171RRI174 from the ChREBP-NLS interacting with ARM2-ARM5 on importin α. We discovered that importin a also binds to the primary binding site of the 14-3-3 proteins with high affinity, which suggests that both importin α and 14-3-3 are each competing with the other for this broad-binding region (residues 117-196) on ChREBP. We screened a small compound library and identified two novel compounds that inhibit the ChREBPNLS/importin α interaction, nuclear localization, and transcription activities of ChREBP. These candidate molecules support developing inhibitors of ChREBP that may be useful in treatment of obesity and the associated diseases. [ABSTRACT FROM AUTHOR]